Embodiments of the inventive concept described herein relate to The inventive concept relates to a dissolved ozone removal unit that removes dissolved ozone from liquid, an apparatus for treating a substrate, a method of removing dissolved ozone, and a method of cleaning a substrate.
In general, in process of manufacturing flat panel display devices or semiconductors, various processes such as a photoresist coating process, a developing process, an etching process, and an ashing process are performed in a process of treating a glass substrate or a wafer.
In particular, as circuit patterns have rapidly become finer as the semiconductor devices have had high density, high integration, and high performance, contaminants such as particles, organic contaminants, metallic contaminant residing on a surface of a substrate greatly influence the characteristics and yield rate of the devices. Due to this, a cleaning process of removing various contaminants attached to a surface of a substrate is very important, and a process of cleaning a substrate is performed before and after unit processes for manufacturing a semiconductor.
Meanwhile, a treatment liquid used in the cleaning process may include ozone of high density, and dissolved ozone has to be removed from the treatment liquid that has performed a process of treating a substrate.
The method of removing dissolved ozone includes a method of removing dissolved ozone by using a catalyst, a thermal decomposition method, and a method of removing ozone by using ultraviolet rays.
The method of removing dissolved ozone by using a catalyst includes a method of removing dissolved ozone by using a surface of active carbon through a direct reaction of active carbon and ozone. Unlike this, there is a method of decomposing dissolved ozone by using manganese dioxide that is a metal oxide.
The thermal decomposition method is a method of removing dissolved ozone by using a property of ozone, by which ozone is converted to oxygen if heat is applied to the ozone.
The method of using ultraviolet rays may include a method of expediting decomposition of ozone by applying ultraviolet rays to the ozone.
Meanwhile, in the method of removing dissolved ozone by using a catalyst, catalysts have to be periodically replaced due to their limited life spans. Further, the thermal decomposition method and the method using ultraviolet rays consume much electric power because much heat and much energy of ultraviolet rays are provided to an ozone removal apparatus.